Treatment of wheat, rye, and other cereals, and bran



Patented Aug. 2, 1949 TREATMENT OF WHEAT, RYE, AND OTHER CEREALS, AND BEAN Cyril Harry Evans, Snaresbrook.

London, England No Drawing. Application rial No. 410,078. In Gre September 8, 1941, Seat Britain January 23,.

Section 3, Public Law 690, August 8, 1946 Patent expires January 23, 19.60

4 Claims. (Cl. 99-232) The invention relates to the treatment of wheat, rye and other cereals and bran for the purpose of improving the quality and colour of flours made fronrsuch cereals and for the purpose of bleaching bran.

It is known in the milling industry that flour may be bleached, and a variety of chemical agents are known for the purpose, such as chlorine, the oxides of chlorine, hydrogen peroxide and nitrogen trichloride. The bleaching eilect is probably due to the conversion of the carotene or related yellow colouring matter of the flour into an oxidised or addition compound which is colourless. In the case however of low grades of flour bran powder is unavoidably and unextractably mixed with the flour and the colour of the flour is to a large extent due to the admixture with it of the bran powder. The known flour bleaching agents do not affect the colour due to the presence of the bran powder in the flour, and some agents, such for example as nitrogen tri-chloride, actually accentuate it. There are however certain bleaching agents which are efiective to bleach both the carotene or related pigment and the bran pigments but the amount of such agents needed to bleach the bran is so much greater than the amount necessary to bleach the flour that the treatment deleteriously afiects the flour with respect particularly to its bakin properties.

It is known to bleach bran and wheat with sulphur dioxide or stannous chloride, that is to say, substances which are chemical reducing or oxygen removing agents, applied in various ways, but while bran is effectively bleached the endosperm is ruined for baking purposes if the agents are applied to the whole grain.

According to the invention the whole wheat before milling or the bran separately is treated not with reducing agents but with oxidising agents in the presence of moisture whereby the product is bleached and in the case of wheat the baking properties of the endosperm are not affected or are improved.

According to the invention moreover, the bleaching agent may consist of oxides of chlorine, either chlorine dioxide in a gaseous form or in solution, or chlorine monoxide as a gas or in a solution as hypochlorous acid or hypo-chlorites.

The oxides of chlorine used in the bleaching it treatment of the wheat or other cereal or bran may be produced in any suitable manner. Thus, chlorine dioxide may be produced by the use of substances which act as carriers thereof, such as sodium chlorite or other chlorites. The gaseous mixture of chlorine dioxide and chlorine produced according to the process and by apparatus of the kind described in the specification of the application Serial No. 254,117, new Patent No. 2,344,346, may advantageously be used. The gas or gas mixture may however be produced in any suitable manner,

In carrying the invention into effect in the treatment of wheat, the process may be carried out in a number of ways, either by preliminarily damping the wheat with a solution of the bleaching gas or by adding the bleaching gas to the water used to wash the wheat, or by applying the bleaching gas to the wet wheat after washing, care being taken in each case to ensure against the endosperm being deleteriously aiiected by the gas so that in effect only the pigment in the husk is bleached by the gas. It is found that bran resulting from wheat treated according to the process of the invention or bran that has been treated alone separately from the wheat is of improved colour and after removal of any gas remaining, as by washing or aspiration, it is free from taint or other objection. It has furthermore been found that the wheat or other cereal treated in accordance with the process of the invention is sterilised and that the possibility of the occurrence of rope in bread produced from flour made from this wheat is avoided. Flour milled from wheat so treated, particularly from. red wheat, is of improved colour, and low grade flour, by reason of the bleaching of the bran powder resulting from the bleaching of the husk of the wheat, is greatly enhanced in colour without detriment to the flour.

The invention is not limited to the manner in ,which the oxidising treatment on the wheat, or

other cereal or bran may be carried out and any convenient apparatus may be used provided that in the treatment sufiicient contact is obtained between the oxidising reagent and the wheat or other cereal or bran; thus the gas in dilute condition may be passed through the vessel in which the wheat or other cereal is being preliminarily damped or washed in known manner.

The proportions of the oxidising agent used with wheat may in general be from 2 to 8 ozs. per 280 lbs, but the amount required depends upon the extent of the bleaching intended. The precise quantity for bleaching to the extent required may be determined by trial. In general the oxidising agent may be used in quantity sufficient to bleach the wheat to the colour of socalled white whea When using chlorine dioxide dilution with air is essential.

When using a gas it is convenient to bring the I claim:

1. A method of treating wheat, rye and other cereals, consisting in bleaching the pigment of the husk of the cereal before milling by the action of an oxide of chlorine, in the presence of moisture sufficient to permit the de-colourising reaction, but insufficient to afiect the properties of the grain in the subsequent milling operation.

2. A method of treating wheat, consisting in bleaching the pigment of the husk of wheat before milling by the action of an oxide of chlorine in a proportion varying from 2 to 8 ozs. per 280 lbs. in the presence of moisture sufilcient to permit the de-colourisation but insufficient to affect the properties of the grain in the subsequent milling operation.

3. A method of treating wheat, rye and other cereals, consisting in bleaching the pigment of the husk of the cereal before milling, by the action of an oxide of chlorine, aiter first damping the husk with a solution of an oxide of chlorine in water, to an extent sufficient to permit the de-colourising reaction, but insuflicient to affect the properties of the grain in the subsequent milling operation.

4. A method of treating wheat, rye and other cereals, consisting in bleaching the pigment of the husk of the cereal before milling, by the action of an oxide of chlorine, by actin thereon with a carrier of chlorine dioxide of the type represented by the chlorites, in th presence of moisture sufiicient to permit the de-colourisation reaction, but insufficient to afiect the properties of the grain in the subsequent milling operation.

CYRIL HARRY EVANS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS OTHER REFERENCES Sodium Chlorite, Properties and Reaction in Industrial and Engineering Chemistry, July 1940, pages 899 through 903.

' Cereal Chemistry, November,1941, pages 699 through 704. 

